This invention relates to an improved femoral component which forms a part of a total hip replacement prosthesis system. The improved femoral component includes a stem portion and a head and neck portion with the head and neck portion having an end comprising a basalar neck portion and a tapered portion inserted into a recess formed at one end of the stem portion. The following prior art is known to applicant:
U.S. Pat. No. 3,067,740 to Habosh discloses a two part insert wherein the head and neck portion thereof is provided with a sleeve which fits over a threaded and splinted end of the stem and is secured with the cap nut. The stem is of a four lobed cross-sectional design and tapers from its proximal to its distal end.
U.S. Pat. No. 3,806,957 to Shersher discloses a femoral insert having a head and neck portion which has a threaded split shank which fits into a socket in the proximal portion of the shaft and is secured by a wedge-shaped screw lock.
U.S. Pat. No. 3,874,003 to Moser, et al. discloses an artificial hip prosthesis wherein the spherical head portion thereof has a recess which fits over a pin extending from a shoulder of the respective stem. At the region of the recess, the stem shoulder has a radially extending collar. Pegs located on the head cooperate with respective depressions in the collar to prevent relative rotation between the head and the pin.
U.S. Pat. No. 3,906,550 to Rostoker, et al. discloses a prosthetic device including a fiber metal attachment structure 18 which comprises a plurality of tubular fiber metal segments which surround the stem portion of the femoral component and promote bony ingrowth therein.
U.S. Pat. No. 3,918,441 to Getscher discloses a two piece insert designed to brace a fractured femur and includes a shaft and head portion which cooperate with one another to receive and distribute weight evenly through the bone. The shaft and head portion are joined by means of a tongue and groove connection and are retained in a joined configuration by a set screw.
U.S. Pat. No. 3,987,499 to Scharbach, et al. discloses a three part implant made of a metallic material coated with enamel and further comprising a threaded anchoring part to which is secured an angled transition part by means of a screw or bolt. The free end of the transition part is threaded to receive a ball head including an intermediary collar thereon.
U.S. Pat. No. 4,001,897 to Rambert, et al discloses a femoral prosthesis including a spherical head which includes a pin therewith which fits into a collar located on an associated shank and which is secured thereto by means of a bolt.
U.S. Pat. No. 4,030,143 to Elloy, et al. discloses a prosthesis intended for use in the shoulder area which includes a scapular component having a multitapered shank consisting of a wide portion at the area of the shoulder and which curves to a tapering tail portion at a remote location thereof.
U.S. Pat. No. 4,031,571 to Heimke, et al. discloses a hip endoprosthesis wherein the stem portion which is inserted into the femur is provided with a stepped configuration which acts to distribute the forces in the bone tissue. Aslo disclosed therein, is the use of a ceramic material which promotes bone formation on the surface of the implant.
U.S. Pat. No. 4,051,559 to Pifferi discloses a two piece femoral insert wherein the head and neck portion thereof is angularly attached to a wedged portion from which depends a pin member. The pin member fits into the upper portion of a cylindrical helically threaded hollow shank and is secured therein in a fixed manner by means of a threaded bolt.
U.S. Pat. No. 4,068,324 to Townley, et al. discloses a hip joint prosthesis including a femoral portion made of one piece. The femoral portion includes a head and neck which neck merges into a platform from which depends an elongated stem portion which is inserted into the medullar cavity of the femur.
U.S. Pat. No. 4,115,875 to Rambert, et al. discloses a femoral prosthesis having a shank the upper face thereof being provided with a bore which is threaded toward the bottom thereof. The femoral head has a conically shaped neck with corresponding threads to engage those in the above described bore.
U.S. Pat. No. 4,261,063 to Blanquaert discloses a femoral insert having a stem of irregular shape which is surrounded by a lattice of titanium wire of a mesh size. The stem has longitudinal grooves and transverse notches and may, if desired, also be made of a titanium alloy containing, for example, six percent aluminum and four percent vanadium. The lattice structure above described is attached to the stem by means of two strips of titanium or other alloy which are placed on the outside of the lattice and electron welded to the stem.
European Pat. No. 001,743 to Schider discloses a joint prosthesis including a ball 1 attached to a neck 2 at 6. The neck 2 is inserted into a cavity formed in a stem portion 3 which stem portion 3 is inserted into the femur.
A publication entitled "The Original M. E. Muller Straight Stem-Femoral Head Prostheses" discloses a femoral component including a stem portion with a neck extending upwardly therefrom and a head portion having a hole therein which fits over the stem neck. As disclosed therein, the device includes a plurality of different stem sizes and a plurality of different head sizes which may be combined together to form a femoral component of the proper size for a particular use.
Publication entitled "BETA Universal Hip System" discloses a femoral component including a head portion with a hollow neck which fits over an upstanding portion of the respective stem.